Why does boron not always continue the period 2 pattern of reacting by losing electrons, as do beryllium and lithium?

Elements in Period 2 such as Barium and Beryllium can lose up to two electrons when they react, however Boron can lose up to three electrons when it reacts which causes it to break the pattern normally seen in Period 2.

Answer;

because its a metalloid and the rest are all metals

Explanation;Boron is a non metallic element and the only non-metal of the group 13 and a member of period 2 of the periodic table the elements. It is a metalloid as it posses both metallic and non-metallic characteristics.Boron's reactivity is comparable to that of other elements in group 13 at very high temperatures. Unlike Boron, the metals in the group are good conductors under normal conditions. Boron is a good conductor only at high temperatures. Beryllium and lithium  are metals and unlike boron they react by loosing electrons. Beryllium reacts by loosing two electrons while lithium reacts by loosing one valence electrons.